Traffic signal with shutter means

ABSTRACT

A traffic control signal or a conversion unit therefor having a shutter which is unrolled across the lens of an amber caution light when illuminated so as to progressively decrease its illuminated area in the direction of the red stop light, and thereby indicating the elapse of time until the red stop light is energized. The shutter is connected to a rotatable drum operated by a motor simultaneously energized with the amber light and a spring acts to reroll the unrolled shutter when the motor is deenergized with the lamp of the amber light.

it States Patent [72] Inventor Wayne Emil Jensen P.0. Box 325, Glenwood, Ill. 60425 [21] Appl. No. 761,547 [22] Filed Sept. 23, 11968 [45] Patented Nov. 2, 1971 [54] TRAFFIC SIGNAL WITH SHUTTER MEANS 20 Claims, 7 Drawing Figs.

[52] US. Cl 340/43 [51] Int. Cl 608g 1/096 [50] Field of Search 340/43, 125, 126

[ 56] References Cited UNITED STATES PATENTS 2,285,168 6/1942 Peterson 340/43 2,349,355 5/1944 Kepler 340/43 3,289,629 l2/l966 Yarger 340/43 3,401,372 9/1968 Smoot .4 340/43 Primary Examinerl(athleen H. Claffy Assistant Examiner-Randall P. Myers Atlorney-Dienner, Johnson, Emrich, Verbeck & Wagner ABSTRACT: A traffic control signal or a conversion unit therefor having a shutter which is unrolled across the lens of an amber caution light when illuminated so as to progressively decrease its illuminated area in the direction of the red stop light, and thereby indicating the elapse of time until the red stop light is energized. The shutter is connected to a rotatable drum operated by a motor simultaneously energized with the amber light and a spring acts to rerolll the unrolled shutter when the motor is deenergized with the lamp of the amber light.

PATENTEU NW2 I97! HG. B

SHEET 1 BF 3 IFIIG. 2

INVENTOR WAYNE E. JENSEN ATTORNEYS *PATENTEUNUVZ 197i 3.618.005

SHEET 3 OF 3 ATTORNEYS TRAFFIC SIGNAL WITH SHUTTER MEANS The invention relates to a new, improved construction of traffic control signal or light and particularly to a conversion unit which can be readily mounted to existing trafiic signals.

A principal object of the invention is to provide means for modifying the customary amber light signal which precedes the red stop light so that it will also be an indicator of the time which remains before the red light is energized and traffic controlled thereby must halt. However, the invention may also be utilized with the green go and red stop lights of such traffic signals to indicate time elapse and/or a traffic flow pattern.

In conventionally operated traffic signals which are designed to control the flow of both automotive and pedestrian traffic an amber lens is positioned intermediate the upper red stop light and the lower green go light. This amber lens is illuminated as the green light goes off and in turn goes off as the red stop light is illuminated. However, an approaching pedestrian or automobile driver is not thereby made aware of how much time remains before the red stop light will come on, and the individual may elect to proceed into the intersection on the erroneous supposition that he has sufficient time in which to cross the intersection before the amber light changes to red and signals the cross traffic to proceed. In accordance with the present invention, however, an expandable shutter is disposed between the amber lens and the lamp which illuminates it, the shutter being operated by the circuit which controls energizing the lamp so that the shutter expands to decrease the illuminated area of the amber lens and thereby advise oncoming traffic of the time which remains before the red stop light signal will signal the traffic to halt.

An important feature of the invention is that although the decreasing area size of the illuminated amber lens is thereby utilized to indicate elapse of time, the brightness of the illuminated amber lens is not reduced. It therefore remains as a readily visible signal to the oncoming traffic, pedestrian or automotive.

Another important feature of the invention is that although the brightness of the illuminated amber lens does not change with its decrease in area size, the shape of its illuminated area does change and this is caused to occur in the direction ofthe red stop light so as to call the attention of the oncoming traffic to the red stop light which illuminates as illumination of the amber light is cutoff.

In one form of the invention, the expandable shutter comprises a roll of opaque flexible sheet or curtain material which is unrolled across the lens therebetween and the lamp from bottom to top wherefore the illuminated area of the amber lens decreases both in size and also shape, going to extinction adjacent the red stop light as it goes on, but while maintaining its brilliance throughout the full period of its illumination.

A further feature of the invention is that the illuminated area of the amber lens is caused to progressively decrease and change its shape at a rate such that the size and shape of the illuminated area of the amber lens approaches zero as the red stop light is illuminated wherefore the fractional size of the illuminated area of the amber lens corresponds to the remaining fraction of its illumination period.

A second, but no less important, object of the invention is to provide a conversion unit that is compatible with existing equipment.

Thus in a preferred embodiment of the invention, the shutter and its actuating means are mounted on a frame which can be readily mounted on the traffic signal in the original place of the amber lens mount. This frame also has means by which the amber lens mount may be then secured thereto so that the expandable shutter operates between the amber lens and its illuminating lamp. In its new arrangement the amber lens and mount then will be disposed forwardly of its original place by the thickness of the added frame.

In a preferred form of the invention, the expandable shutter comprises a roll ofopaque sheet material as described which is mounted on the frame so as to be disposed below the amber lens and the actuating means comprising a motor rotated shaft supporting a pair of spaced winding drums or pulleys is mounted on the frame above the lens, the drums being connected to the shutter roll as by flexible wire cables, cords or the like. In one form of the invention, the actuating means also includes a solenoid-operated clutch which releaseably clutches the drum supporting shaft to the motor, both the motor and the solenoid being simultaneously energized with the lamp. The solenoid acts on the shaft so as to clutch it to the motor arbor as the motor is energized, wherefore the shutter unrolls across the amber lens with rotation of the motor.

Because both the motor and the solenoid which clutches the drum rotating shaft to the motor deenergize as the amber light deenergizes, a relatively light torsion spring may be utilized to reroll the shutter, the spring being tensioned in the unrolling of the shutter.

In a second form of the invention, the motor directly couples to the winding shaft to raise the shutter when the amber light is energized and tensions the shutter spring, said spring then taking over to reroll the shutter when the motor is deenergized with the amber light.

Thus an exceedingly simple and uncomplicated, yet efficiently and effectively operating shutter for the amber signal is provided.

Furthermore, although the shutter adapts the illuminated amber light to also give a visual indication of the time remaining between the green and red lights, the light emitted by the amber lens is not lowered in intensity or brightness during any portion of its illuminated period.

A feature of the invention therefore is that it comprises a conversion unit which can conveniently installed on existing traffic signal structures with a minimum amount of inconvenience. It can also be readily weatherproofed.

A further feature of the invention is that the motor, and solenoid if employed, can be readily wired into the control circuit for the amber lens illuminating lamp and so that the solenoid and/or motor are energized only during the interval the amber lens is illuminated. Operational costs therefore are not materially increased.

Still another feature of the invention is the compactness of the structure which comprises the conversion unit and which makes it readily adaptable for mounting on an existing traffic signal structure.

Many other objects, advantages and/or features of the invention will be at once apparent or will become so upon consideration of the mentioned embodiments of the invention which will now be more particularly described in connection with the figures of the accompanying drawings.

Referring therefore to the said drawings FlG. l is a front elevational view of a traffic signal light modified in accordance with the present invention;

FIG. 2 is a side elevational view thereof;

FIG. 3 is a front elevational view of the conversion unit, the amber lens and its supporting mount having been removed;

FIG. 4 is a vertical sectional view taken through said conversion unit and indicates the relationship of the shutter and its actuating means to the amber lens and the reflector and lamp which illuminates the lens;

FIG. 5 is a schematic plan of the wiring of a traffic signal light modified in accordance with this invention;

FIG. 6 illustrates a second embodiment of the invention wherein the solenoid has been omitted; and

FIG. 7 is a sectional view taken through FIG. 6 along lines Referring therefore now more specifically to the several views wherein like parts are identified by like reference numerals, in FIG. I, 10 represents the housing of a traffic signal light of conventional construction which, however, has been modified in accordance with the present invention by addition ofa conversion unit 40 (FIG. 2) as is hereinafler more specifically described. Housing 10 is divided into at least three lamp chambers identified in FIG. l as 10a, 10b, and 100. Each of said chambers contains a separately illuminated light bulb and associated reflector by means of which a coloredlens positioned forwardly thereof on the traffic facing side of the signal light may be rear-illuminated. Thus in FIG. 1, 14 represents a red colored lens rear illuminated by a lamp 16 (FIG. in the upper chamber a which when lighted serves to signal approaching traffic to come to a halt. 18 represents a green colored lens which is rear-illuminated by lamp 20 in the lower chamber 101: of the housing, and which when lighted signals that the halted and oncoming traffic may proceed through the intersection. 22 represents an amber colored caution lens which is rear-illuminated by lamp 24 in an intermediately located chamber 10b between the upper and lower chambers. Amber colored lens 22 is conveniently lighted for a controlled period of time between the darkening of the green colored go" lens 18 and the lighting of the red colored stop lens 14 and warms oncoming traffic in advance of the changing signals, providing for oncoming traffic which has entered the intersection to clear before the red colored stop" light is illuminated and cross traffic is signaled to proceed into the intersection.

As schematically illustrated by FIG. 5, each said lamps 16, 20 and 24 are wired into a time control device indicated generally at 26 which is connected to a suitable power source and serves to regulate the time interval and sequence in which each of said lamps is illuminated.

As shown in FIGS. 1 and 2, each of said colored lenses I4, 18 and 22 is supported on its own mount or panel and are suitably hinged to one wall of the housing 10 so that they may be swung open to provide access into lamp chambers 10a, 101;, or 100 for replacement of bulbs and other maintenance activity. Thus, as illustrated in said FIGS. 1 and 2, each of panels 12 has a pair of spaced ears 28 which are pinned to a corresponding pair of ears 30 on the exterior of the housing 10 to constitute a hinged connection. Suitable means are also provided for releasably locking each lens mounts or panels 12 to the housing 10. As shown in FIG. 1, each said panels has a bifurcated portion 32 on its side opposite that bearing hinge ears 28. A suitable catch in the form of an externally threaded stem member 34 is pivotally connected at 36 to the adjacent wall of the housing 10, as for example illustrated in FIG. 3, and a winged nut 38 threadedly connects to said free end of the stem 34 which is tightened on the stern when positioned between the bifurcations of projection 32 so as to securely, but releasably, lock the respective panels over the respective chambers of the housing 10. As thus far described, the illustrated traffic signal light is of conventional construction.

In accordance with the present invention a conversion unit 40 may be mounted over one or more of said chambers 10a, 10b, or 10c therebetween and its associated lens supporting panel 12. Such a conversion unit comprises an expandable or movable shutter and actuating means for operating the same in order to change or control the illuminated area of the lens with which it is associated. In the embodiment of the invention represented by FIGS. 1 through 5 which will be described now, this conversion unit is shown positioned over the intermediate chamber b, the bulb or lamp of which illuminates the amber colored caution lens 22. However, the conversion unit could as well be associated with the green go lens and/or with the red stop" lens if it were also desired to indicate the lapse of time of said signals to the oncoming trafiic.

As shown in FIGS. 2, 3, and 4, such a conversion unit 40 comprises a generally rectangular or other appropriately shaped frame 42 which is hinged to ears 30 of the housing 10 in place ofthe panel 12 which supports the amber colored lens 22. Panel 12 is in turn hinged to the conversion unit frame 42. For this purpose frame 42, as illustrated in FIG. 2, is provided with a pair of hinge bearing brackets 44 spaced along one side, each comprising a first ear 46 which pivotally connects to one of the two ears 30 of the housing 10 associated with said lamp chamber and second ear 48 to which one of the two ears 28 of the panel 12 supporting the amber colored lens 22 may be also hinged. Thus panel 12 may be opened as before by pivoting on ears 46 so as to gain access to the interior of the conversion unit frame 42 and additionally the conversion unit may be simultaneously or successively swung by its cars 46 on cars 30 of the housing 10 to gain access into the interior of the lamp housing chamber l0b,for example. Panel 12 is secured in place as before. However, to compensate for the greater spacing of projection 32 from pivotal mount 36 introduced by the thickness of the conversion unit frame 42, it may be necessary to replace stem 34 by a longer catch, identified at 34a in FIG. 3. Said stem 34a thus serves by tightening wing nut 38 on the threaded outer or free end of catch 34a to releasably secure both the conversion unit 40 and the outer lens supporting panel 12 to the housing 10.

As illustrated in FIG. 4, the inner side of the conversion unit 40 may be provided with a gasket at 49 by which it may be made weathertight against the outer edges of the traffic signal light housing 10 surrounding chamber 10b. Panel 12 is conventionally provided with a gasket 50 seating in a provided recess on its inner side and wall 42 of the conversion unit is so shaped and dimensioned that when panel 12 is locked thereagainst by the mentioned wing nut 38 and catch 340, said gasket 50 engages against the opposite side edge of said frame 42 of the conversion unit. Thus the tightening of wing nut 38 on stem 34a, effectively weatherproofs the conversion unit and its mounting over lamp chamber 10b.

Referring now more specifically to FIGS. 3 and 4, and as previously mentioned, conversion unit 40 comprises both an expandable shutter supported by frame 42 between lens 22 and lamp 24 and actuating means therefor. The expandable shutter may comprise a diaphragm which is spring-tensioned to close under the actuation of a motor in timed sequence to the duration for which said lamp 24 is illuminated and to reopen when the motor is deenergized. However, in the embodiment illustrated by FIGS. 3 and 4, such a shutter indicated generally at 51 comprises a sheet 52 of opaque flexible material such as clothbacked rubber, having one end tacked or otherwise secured to a roller 54 about which it is rolled or wrapped. As shown in FIG. 3, said roller 54 is supported in a pair of suitable bearing mounts 56 and 58 so that it extends lengthwise of the chamber 10a and below the illuminated area of lenses 22. Shutter 52 has a width at least as great as, and preferably greater than the greatest horizontal dimension of the lens 22 so as to completely shut off illumination of that portion of the lens covered thereby. It also has length such that it may be unrolled and raised between the lens 22 and the lamp 24 to completely shut off illumination of the lens. Any suitable actuating means may be employed for so raising shutter 52.

In the the embodiment of the invention illustrated by FIGS. 3 and 4 the free edge of shutter 52 is secured to a pair of spaced connectors 58 having their opposite ends wound about winding drums or pulleys 62 and secured thereto by set screws 64 which also secure said drums to a supporting shaft 66. Connectors 58 may be comprise any suitable flexible members capable of being wound on pulleys 52. For example they may comprise cords of nylon, fiberglass, link chains, cables or strands of stainless steel wire, braided wire, rope, etc. As illustrated best in FIG. 3, supporting shaft 66 has one end rotatably supported in a suitable bearing 68 adjacent the upper sidewall of the conversion unit 40, its other end rotatably seating in a clutch element 70 mounted on the arbor 72 of a 1 l0-volt AC synchronous motor 74 which is suitably secured to frame 42 of the conversion unit as by support 75. Shaft 66 is coaxially aligned with said motor arbor 72, and winding drums or PM leys 62 adjacent clutch 70 is provided with a friction surface 70' on its side toward the clutch member 70 which may be caused to engage the clutch member by winding shaft 66 to the left of FIG. 3 so as to be effectively coupled to the motor 74 Axial movement of shaft 66 is obtained by means of a solenoid 76 shown supported above shah 66 to frame 42 of the supporting unit as by a pair of brackets 78. Considering FIG. 3 with FIG. 5, it will be understood that solenoid 76 has an armature 80 pivotally connected at its outer or free end to an articulated linkage system comprising a first link 82 and a second link 64, link 64 being pivotally connected to the opposite end of link 62 in turn pivotally connected adjacent its lower end to the bracket 66 as at 66 and so that a portion thereof is to the right of shaft 66 on which winding drums 62 are supported. As shown in FIG. 5, when the timer control 26 energizes lamp 24 is also simultaneously energizes motor 74 and solenoid 76 which are connected in parallel with the lamp 24. Motor 74 therefore starts to rotate its arbor 72. Simultaneously solenoid 76 acts to withdraw armature 60 into the interior thereof whereupon the articulate linkage system represented by links 62 and 84 reacts causing link 64 to engage the end of shaft 66, moving shaft 66 and the friction surface of the left-hand winding drum 62 into engagement with clutch 76 so that the shaft 66 turns with the motor. Consequently shaft 66 is clutched to the operating motor 74 as the motor is energized with lamp 24 causing winding drums or pulleys 62, 62 to wind connector cable or cords 58 thereon and so as to raise the shutter 52 across the amber lens 22 therebetween and the illuminated lamp 24.

The diameter of the winding drums or pulleys 62 is related to the r.p.m. of motor 74 and the duration for which lamp 24 is energized so that it takes the whole interval for which the amber lens is illuminated to raise the shutter 52 to the top of lens 22. In an alternate form of the invention, the diameter of the drums is such that the shutter is raised to its full extent before the time control 26 deenergizes lamp 24 and motor 74; and a time delay switch device 66 is positioned in the path of the rising shutter to be actuated as it reaches its upper limit. Switch 86 is indicated in FIGS. 3 and 5 and is generally closed but when tripped by shutter 52 opens to deenergize the motor 74 and solenoid 76 and thereafter remains open long enough to allow shutter 52 to be rerolled on roller 54. The amber colored lens 22 in this form is therefore again momentarily fully illuminated before lamp 24 is deenergized.

As illustrated in FIG. 3, roller 54 includes an internally located tension spring 90 having one end fixed within the roller and its other end fixed to portion 92 of the roller which is held nonstationary in bearing support 56. The other end of the roller is free to rotate in bearing 56. Thus as shutter 52 is raised through the operation of motor 74, spring 90 is tensioned so that upon deenergizing of motor 74 and solenoid 76, the tension of spring 90 takes over to assist gravity in the lowering of the shutter and rerolling it onto the roller 54.

It will be understood that shutter 52 is opaque so that it completely shuts off all illumination of the lens 22 therethrough but does not at all interfere with the brightness of the lens area above the shutter which remains illuminated by the lamp 24. Thus, as illustrated in FIG. 1, for example, half-way through the period of illumination of lamp 24 the shutter causes the lens 22 to present a brightly illuminated half-moon or semicircular shape. For maximum efficiency it will be appreciated that the shutter 52 should be located as close to the rear surface of the lens 22 as is practical. It will be understood also that it is unnecessary that shutter 52 rise to a height which completely cuts off all illumination of the lens surface 22. Usually it will suffice if the shutter can rise to a height which only approaches full cut off before the lamp 24 is deenergized, the effect being the same. Although the winding drum 62 has been described and illustrated in FIGS. 3 and 4 as connected to the shutter 52 by cords or cables 56 which are wound on the drums or pulleys 62 to effect raising of the shutter, any other suitable means for unrolling the shutter off the roll in response to energizing of motor 74 may also be utilized.

Referring now to FIGS. 6 and 7 a second embodiment ofthe invention is illustrated wherein shaft 66 which supports the winding drums or pulleys 62 is directly coupled to motor shaft 72 or made integral therewith. In this arrangement clutch 70 and solenoid 76, as well as the articulated linkage represented by links 62, 64 is omitted. In this simplified structure the operation is, however, substantially the same as in the first described embodiment of FIGS. 3 and 4. Thus when the timer control 26 energizes lamp 24 with which the conversion unit is utilized, motor 74 is simultaneously energized and starts to rotate shaft 66 to which it is directly coupled. Winding drums 62 therefore start to wind flexible connectors 56 thereon and so raise the shutter 52 across the rear surface area of lens 22 and so as to progressively cut off illumination of said lens and in the direction of the upper located red colored lens 14 next to be illuminated. Simultaneously, spring in roller 54 is tensioned by the unrolling of shutter 52. When motor 74 is deenergized by the timer control 26 turning off lamp 24 or the rising shutter 52 actuating trip control switch 65 and shaft 66 which is now freely rotatable in motor 74 allows the tensioned spring 90 to reroll the shutter on roller 54 and so as to reposition the shutter for the next illumination of the amber lens 22. In other respects the conversion unit illustrated by FIGS. 6 and 7 is as described above in connection with FIGS. it through 5. However, in this embodiment the flat shaped gasket 49 is shown replaced by a hollow rubber sealing gasket 94 seated in a suitable recess.

It will thus be understood that in each embodiment the lens with which the conversion unit is utilized is initially fully illuminated when its associated lamp is turned on by the timer control 26. Shutter 52, however, as it is raised serves to progressively darken the illuminated area of the lens to indicate the elapse of time and thereby to provide the oncoming traffic with information as to the remaining interval of time before the next change of light signal.

Thus, it will be apparent that all of the recited objects, advantages and features of the invention have been demonstrated as obtainable in a highly practical and efiicient manner. For example, as noted above, the conversion unit 40 is simply mounted on an existing traffic light signal in the place of the lens mounting panel 12 which is first removed from over the lamp chamber with which the conversion unit is to be secured. The mounting panel 12 is then reattached to the con version unit. After the conversion unit has been mounted as described, motor leads 98 are connected to the terminals of the lamp 24 associated with the amber lens. Thus no modification or restructuring of the traffic signal is required beyond perhaps substituting a longer stemmed catch 34. Neither is any rewiring required.

Thus having described my invention, I claim:

1. A traffic signal conversion unit comprising a frame mountable between a lens and illuminating means therefor contained in the traffic signal, a shutter mounted on said frame and expandable across the lens therebetween and the illuminating means so as to progressively change the area of the lens exposed to the illuminating means, and actuating means mounted on the frame which operatively connects to the electrical control circuit for said illuminating means so as to be energized to operate said shutter only in the time interval that the lens is illuminated and so progressively change the illuminated area of the lens during said time interval.

2. A traffic signal conversion unit as claimed in claim 1 wherein the actuating means includes a motor and clutch means drivingly connecting the shutter to the motor only during the interval the illuminating means operates to illuminate the lens.

3. A traffic signal conversion unit as claimed in claim 1 wherein the lens is located between a. pair of traffic control lights which are successively energized, the lens being illuminated by the illuminating means between the deenergizing of one of said traffic control lights and the energizing of the other, the shutter being operated during the illumination of said lens to progressively change the illuminated area thereof in the direction of the one of said traffic control lights next to be energized.

4. A traffic signal conversion unit as claimed in claim 1 wherein the lens and illuminating means comprise an amber caution light which is illuminated prior to illumination of a traffic control light, the expandable shutter progressively decreasing the illuminated area of the lens such that the lens goes dark as the traffic control light is illuminated.

5. A traffic signal conversion unit comprising supporting structure mountable between a lens and a lamp contained in the traffic signal, an opaque shutter mounted on said structure so as to be drawn between the lens and lamp from one side of the lens to the other side thereof to progressively decrease the area of the lens exposed to the lamp, and means mounted on the structure which operatively connects to the electrical control circuit for said lamp so as to be energized only during the interval that the lamp is illuminated to draw said shutter across the lens therebetween and the lamp, said means drawing the shutter across the lens at a rate such that the progressively decreasing illuminated area of the lens indicates the remaining fraction of the illuminated period of the traffic signal light.

6. A traffic signal conversion unit as claimed in claim 5, wherein the lens is illuminated prior to the illumination of a second traffic control light located to one side thereof, and the shutter is drawn across the lens in the direction of said second traffic control light.

7. In a trafiic signal the combination of a lens, a lamp located behind the lens to illuminate the same on signal from an electrical control circuit, a screen movable between said lens and lamp so as to progressively change the area of the lens exposed to said lamp, and means operatively connected to the electrical control circuit for said lamp so as to be energized to move said screen only during the time interval the lamp illuminates the screen, the progressively changing illuminated area of the lens indicating the remaining fraction of the illuminated period of the traffic signal.

8. The combination of claim 7 when used in conjunction with a second traffic control light, the movable screen reducing the illuminated area of the lens to near extinction as the second traffic control light is energized.

9. The combination of claim 7 when used in conjunction with a second traffic control light, the movable screen progressively changing the illuminated area of the lens in the direction of said other traffic control light.

10. In a trafiic light signal embodying a lamp, a surrounding reflector, an encircling frame extending forwardly of and about said lamp and reflector, and a lens supported by said frame and positioned forwardly of the lamp and reflector so as to be brightly illuminated thereby, the improvement which comprises a rolled opaque shutter supported on a lower portion of said frame below the lens, said shutter having a width and height in its unrolled state greater than the width and height of the lens, a winding drum means rotatably mounted on said frame above the lens, means connecting said rolled shutter to the winding drum means so that the shutter is unrolled and raised in response to the rotation of the winding drum means, a motor and a solenoid each connected to an electrical control circuit for said lamp so as to be simultaneously energized with said lamp and for the time interval that it is energized by said control circuit, the motor having a shaft coaxially aligned with one end of said winding drum means, clutch means disposed between said motor shaft and said end of the winding drum means, said drum means being axially movable in response to energizing of said solenoid so as to be drivingly connected by said clutch means to the motor shaft, the winding drum means when thus clutched to the motor shaft being rotated by the motor to unroll the shutter and raise it between the lamp and lens so as to progressively decrease the area of the lens across the width thereof which is exposed to illumination by the lamp.

11. The improvement in a traffic light signal as claimed in claim 10 wherein the diameter of said drum means is such that the shutter is unrolled and raised to the height of the lens in the time interval that the lamp is energized.

12. The improvement in a traffic light signal as claimed in claim 10 further including spring means tensioned by the unrolling of the shutter, the motor and solenoid being simultaneously deenergized with the lamp so that the winding drum is declutched from the motor shaft when the lamp is deenergized, and the tension of the spring reacting on the shutter to lower and reroll the shutter when the motor and solenoid are deenergized.

13. In a traffic light signal em bodying a lamp, an encircling frame extending forwardly of and about said lamp, and a lens supported by said frame and positioned forwardly of the lamp to be illuminated thereby, the improvement which comprises a rolled opaque shutter supported on said frame to one side of the lens, drum means rotatably mounted on said frame to the opposite side of the lens and connected to the rolled shutter so as to unroll the shutter across the lens in response to its rotation, a motor for rotating said drum means, said motor being connected into an electrical control circuit for said lamp so as to be simultaneously energized therewith and for the time interval that the lens is energized by said control circuit, said motor serving to unroll the shutter across the lens therebetween and the lamp when the lamp is illuminated, and means for rerolling the shutter when the motor is deenergized with the lamp.

14. The improvement in a traffic light signal as claimed in claim 13 wherein the shutter is mounted on a roller including a spring which is tensioned by unrolling the shutter off the roller, said tensioned spring rerolling the shutter when the motor is deenergized with the lamp.

15. In a traffic light signal embodying a lamp, an encircling frame extending forwardly of and about said lamp, and a lens supported by said frame and positioned forwardly of the lamp and reflector so as to be brightly illuminated thereby, the improvement which comprises a rolled opaque shutter supported on a portion of said frame adjacent the bottom edge of the lens, said shutter having a width in its unrolled state greater than the width of the lens, drum means rotatably mounted on said frame adjacent the upper edge of the lens, means connecting said rolled shutter to the drum means so that the shutter is unrolled and raised in response to the rotation of the drum means, a motor connected to an electrical control circuit for said lamp so as to be simultaneously energized thereby, the motor having a shaft coaxially aligned with and connected to one end of said drum means, the drum means rotating with the motor to unroll the shutter and raise it between the lamp and lens so as to progressively decrease the area of the lens across the width thereof which is exposed to illumination by the lamp, the diameter of said drum means being such that the shutter is unrolled and raised to near the height of the lens in the time interval that the lamp is energized, and spring means tensioned by the unrolling of the shutter, the motor being simultaneously deenergized with the lamp so that the drum means is free to rotate when the lamp is deenergized, and the tension of the spring acting on the shutter to lower and reroll the shutter when the motor is deenergized.

16. In a traffic light signal as claimed in claim 15 wherein a circuit breaker is connected into the motor circuit so that the motor deenergizes immediately ahead of the deenergizing of the lamp causing the lens to be again fully illuminated before the lamp deenergizes.

17. A traffic signal conversion unit comprising a frame mountable between a lens and illuminating means therefor contained in the traffic signal, shutter means supported on said frame for interposition between the lens and the illuminating means, a motor mounted on said frame operably connected to a circuit for said illuminating means so as to be simultaneously energized and deenergized therewith, said motor being operatively connected to the shutter means so as to move the shutter means into position between the lens and illuminating means when energized to vary the illumination of the lens during its illumination period to exercise control over traffic flow, and means moving the shutter means out of said position when the motor is deenergized.

18. In a traffic light signal embodying a lamp, a housing therefor and a lens supported forwardly of the lamp to be illuminated thereby, the improvement which comprises an opaque shutter supported between the lens and lamp and adapted to close across the lens to cut off its illumination by the lamp, and operating means for said shutter including a motor having leads by which it may be readily be connected to the terminals of said lamp so as to be simultaneously energized therewith and only for the time interval that the lens is energized, said motor serving to close the shutter across the lens therebetween and the lamp when the lamp is illuminated, and the shutter reopening when the motor is deenergized with the lamp.

19. For a traffic light signal having vertically spaced red, amber and green lenses each removably mounted on one side of the traffic light signal over associated lamps which are successively illuminated on signal from an electrical control circuit into which the associated lamps are electrically connected, a conversion unit comprising a frame mountable to said traffic light signal in the place of one of said lenses and having means by which the removed lens may be mounted to said frame to reassume its position over its associated lamp, shutter means on said frame expandable therein across the Jill area thereof to progressively change the area of the lens which is exposed through the frame to its. associated lamp, electrically actuated means mounted on the frame to operate said shutter, said electrically actuated means having leads by which it is connectable to the terminals of the lamp associated with said lens so as to be energized with the energizing of the lamp, said means when energized expanding the shutter across the area of the frame, and means which return the shutter to its unexpanded condition on deenergizing of said means.

20. The conversion unit of claim 19 wherein its frame has means for hingedly mounting the lens thereto and insulating means which provide a weathertight seal therebetween, the traffic light signal and the lens. 

1. A traffic signal conversion unit comprising a frame mountable between a lens and illuminating means therefor contained in the traffic signal, a shutter mounted on said frame and expandable across the lens therebetween and the illuminating means so as to progressively change the area of the lens exposed to the illuminating means, and actuating means mounted on the frame which operatively connects to the electrical control circuit for said illuminating means so as to be energized to operate said shutter only in the time interval that the lens is illuminated and so progressively change the illuminated area of the lens during said time interval.
 2. A traffic signal conversion unit as claimed in claim 1 wherein the actuating means includes a motor and clutch means drivingly connecting the shutter to the motor only during the interval the illuminating means operates to illuminate the lens.
 3. A traffic signal conversion unit as claimed in claim 1 wherein the lens is located between a pair of traffic control lights which are successively energized, the lens being illuminated by the illuminating means between the deenergizing of one of said traffic control lights and the energizing of the other, the shutter being operated during the illumination of said lens to progressively change the illuminated area thereof in the direction of the one of said traffic control lights next to be energized.
 4. A traffic signal conversion unit as claimed in claim 1 wherein the lens and illuminating means comprise an amber caution light which is illuminated prior to illumination of a traffic control light, the expandable shutter progressively decreasing the illuminated area of the lens such that the lens goes dark as the traffic control light is illuminated.
 5. A traffic signal conversion unit comprising supporting structure mountable between a lens and a lamp contained in the traffic signal, an opaque shutter mounted on said structure so as to be drawn between the lens and lamp from one side of the lens to the other side thereof to progressively decrease the area of the lens exposed to the lamp, and means mounted on the structure which operatively connects to the electrical control circuit for said lamp so as to be energized only during the interval that the lamp is illuminated to draw said shutter across the lens therebetween and the lamp, said means drawing the shutter across the lens at a rate such that the progressively decreasing illuminated area of the lens indicates the remaining fraction of the illuminated period of the traffic signal light.
 6. A traffic signal conversion unit as claimed in claim 5, wherein the lens is illuminated prior to the illumination of a second traffic control light located to one side thereof, and the shutter is drawn across the lens in the direction of said second traffic control light.
 7. In a traffic signal the combination of a lens, a lamp located behind the lens to illuminate the same on signal from an eleCtrical control circuit, a screen movable between said lens and lamp so as to progressively change the area of the lens exposed to said lamp, and means operatively connected to the electrical control circuit for said lamp so as to be energized to move said screen only during the time interval the lamp illuminates the screen, the progressively changing illuminated area of the lens indicating the remaining fraction of the illuminated period of the traffic signal.
 8. The combination of claim 7 when used in conjunction with a second traffic control light, the movable screen reducing the illuminated area of the lens to near extinction as the second traffic control light is energized.
 9. The combination of claim 7 when used in conjunction with a second traffic control light, the movable screen progressively changing the illuminated area of the lens in the direction of said other traffic control light.
 10. In a traffic light signal embodying a lamp, a surrounding reflector, an encircling frame extending forwardly of and about said lamp and reflector, and a lens supported by said frame and positioned forwardly of the lamp and reflector so as to be brightly illuminated thereby, the improvement which comprises a rolled opaque shutter supported on a lower portion of said frame below the lens, said shutter having a width and height in its unrolled state greater than the width and height of the lens, a winding drum means rotatably mounted on said frame above the lens, means connecting said rolled shutter to the winding drum means so that the shutter is unrolled and raised in response to the rotation of the winding drum means, a motor and a solenoid each connected to an electrical control circuit for said lamp so as to be simultaneously energized with said lamp and for the time interval that it is energized by said control circuit, the motor having a shaft coaxially aligned with one end of said winding drum means, clutch means disposed between said motor shaft and said end of the winding drum means, said drum means being axially movable in response to energizing of said solenoid so as to be drivingly connected by said clutch means to the motor shaft, the winding drum means when thus clutched to the motor shaft being rotated by the motor to unroll the shutter and raise it between the lamp and lens so as to progressively decrease the area of the lens across the width thereof which is exposed to illumination by the lamp.
 11. The improvement in a traffic light signal as claimed in claim 10 wherein the diameter of said drum means is such that the shutter is unrolled and raised to the height of the lens in the time interval that the lamp is energized.
 12. The improvement in a traffic light signal as claimed in claim 10 further including spring means tensioned by the unrolling of the shutter, the motor and solenoid being simultaneously deenergized with the lamp so that the winding drum is declutched from the motor shaft when the lamp is deenergized, and the tension of the spring reacting on the shutter to lower and reroll the shutter when the motor and solenoid are deenergized.
 13. In a traffic light signal embodying a lamp, an encircling frame extending forwardly of and about said lamp, and a lens supported by said frame and positioned forwardly of the lamp to be illuminated thereby, the improvement which comprises a rolled opaque shutter supported on said frame to one side of the lens, drum means rotatably mounted on said frame to the opposite side of the lens and connected to the rolled shutter so as to unroll the shutter across the lens in response to its rotation, a motor for rotating said drum means, said motor being connected into an electrical control circuit for said lamp so as to be simultaneously energized therewith and for the time interval that the lens is energized by said control circuit, said motor serving to unroll the shutter across the lens therebetween and the lamp when the lamp is illuminated, and means for rerolling the shutter when the motor is deenergized with The lamp.
 14. The improvement in a traffic light signal as claimed in claim 13 wherein the shutter is mounted on a roller including a spring which is tensioned by unrolling the shutter off the roller, said tensioned spring rerolling the shutter when the motor is deenergized with the lamp.
 15. In a traffic light signal embodying a lamp, an encircling frame extending forwardly of and about said lamp, and a lens supported by said frame and positioned forwardly of the lamp and reflector so as to be brightly illuminated thereby, the improvement which comprises a rolled opaque shutter supported on a portion of said frame adjacent the bottom edge of the lens, said shutter having a width in its unrolled state greater than the width of the lens, drum means rotatably mounted on said frame adjacent the upper edge of the lens, means connecting said rolled shutter to the drum means so that the shutter is unrolled and raised in response to the rotation of the drum means, a motor connected to an electrical control circuit for said lamp so as to be simultaneously energized thereby, the motor having a shaft coaxially aligned with and connected to one end of said drum means, the drum means rotating with the motor to unroll the shutter and raise it between the lamp and lens so as to progressively decrease the area of the lens across the width thereof which is exposed to illumination by the lamp, the diameter of said drum means being such that the shutter is unrolled and raised to near the height of the lens in the time interval that the lamp is energized, and spring means tensioned by the unrolling of the shutter, the motor being simultaneously deenergized with the lamp so that the drum means is free to rotate when the lamp is deenergized, and the tension of the spring acting on the shutter to lower and reroll the shutter when the motor is deenergized.
 16. In a traffic light signal as claimed in claim 15 wherein a circuit breaker is connected into the motor circuit so that the motor deenergizes immediately ahead of the deenergizing of the lamp causing the lens to be again fully illuminated before the lamp deenergizes.
 17. A traffic signal conversion unit comprising a frame mountable between a lens and illuminating means therefor contained in the traffic signal, shutter means supported on said frame for interposition between the lens and the illuminating means, a motor mounted on said frame operably connected to a circuit for said illuminating means so as to be simultaneously energized and deenergized therewith, said motor being operatively connected to the shutter means so as to move the shutter means into position between the lens and illuminating means when energized to vary the illumination of the lens during its illumination period to exercise control over traffic flow, and means moving the shutter means out of said position when the motor is deenergized.
 18. In a traffic light signal embodying a lamp, a housing therefor and a lens supported forwardly of the lamp to be illuminated thereby, the improvement which comprises an opaque shutter supported between the lens and lamp and adapted to close across the lens to cut off its illumination by the lamp, and operating means for said shutter including a motor having leads by which it may be readily be connected to the terminals of said lamp so as to be simultaneously energized therewith and only for the time interval that the lens is energized, said motor serving to close the shutter across the lens therebetween and the lamp when the lamp is illuminated, and the shutter reopening when the motor is deenergized with the lamp.
 19. For a traffic light signal having vertically spaced red, amber and green lenses each removably mounted on one side of the traffic light signal over associated lamps which are successively illuminated on signal from an electrical control circuit into which the associated lamps are electrically connected, a conversion unit comprising a frame mountable to said traffic light signal in the place of one of saId lenses and having means by which the removed lens may be mounted to said frame to reassume its position over its associated lamp, shutter means on said frame expandable therein across the area thereof to progressively change the area of the lens which is exposed through the frame to its associated lamp, electrically actuated means mounted on the frame to operate said shutter, said electrically actuated means having leads by which it is connectable to the terminals of the lamp associated with said lens so as to be energized with the energizing of the lamp, said means when energized expanding the shutter across the area of the frame, and means which return the shutter to its unexpanded condition on deenergizing of said means.
 20. The conversion unit of claim 19 wherein its frame has means for hingedly mounting the lens thereto and insulating means which provide a weathertight seal therebetween, the traffic light signal and the lens. 